1. Field of Invention
This invention is directed to direct marking systems that utilize multiple staggered printheads in order to achieve full width printing per pass. More specifically, this invention is directed to a device and method for the alignment, in six degrees of freedom or less, of multiple printheads in a printer by providing adjustments in up to all six degrees of freedom for each printhead.
2. Description of Related Art
Misalignment of printheads may be due to, for example, poor manufacturing tolerances, thermal expansion of the printhead and associated parts of the printer, vibration of the printhead, or the like. Thus, aligning the printheads with sufficient accuracy to allow high image quality is desired.
Devices for alignment of printheads in a printer are known. For example, U.S. Pat. No. 6,068,415 to Smolenski discloses a printhead that is spring loaded, permitting it to float in both the vertical and horizontal directions. Smolenski also discloses placing the printhead on a comparatively short and rigid pivoting arm.
U.S. Pat. No. 6,298,783 to O'Mera at al. discloses an alignment device for mounting an alignable part, such as a thermal printhead, on a support frame. The printhead is adjustable on the support frame relative to a reference plane about a pivot axis on the support frame and also laterally of the reference plane.
Known mechanisms for alignment of printheads are limited in the number of degrees of translation and rotation of the printhead that can be independently adjusted. This is not suitable since misalignment may occur in any of the six degrees of freedom (translation and rotation). Some existing technologies use an additional alignment mechanism for each increment in degree of freedom. However, this leads to a larger footprint area of the alignment mechanisms, more parts, and thus more thermal expansion and vibration, further leading to misalignment of the printhead.